Former head coach turned NBC commentator Tony Dungy was sitting in the studio and acted as if he'd just unleashed the secret of the NFL season when he said the chink in the Denver Broncos' armor was their defense.

Dungy's colleague Rodney Harrison snickered, then quickly mentioned that the Ravens were playing good defense. He apparently didn't see Sunday's game against the Minnesota Vikings, or taking too many blows to the head when he played was finally starting to have an effect.

No team plays great defense in the NFL anymore, especially in the AFC. The salary cap, rule changes and the creation of more complex systems have given the advantage to the offense, and it could remain that way forever.

The 2002 Tampa Bay Buccaneers were the last dominant defensive team that won a Super Bowl. Before then, it was the 2000 Ravens. We might have seen the last of great defenses like those of the 1985 Chicago Bears, the Pittsburgh Steelers' "Steel Curtain," the Los Angeles Rams' "Fearsome Foursome," the Minnesota Vikings' "Purple People Eaters" or the Dallas Cowboys' "Doomsday."

Just take a look around the NFL. The Seattle Seahawks and Detroit Lions have great personnel, but those teams play well at home and lousy on the road. In the AFC, the Cincinnati Bengals and Kansas City Chiefs have impressive defensive numbers but are both soft.

Denver has quarterback Peyton Manning and that fantastic offense, but the Broncos are also allowing 374.2 total yards per game. The Indianapolis Colts are allowing 372.1 total yards per game, and the New England Patriots are ranked No. 31 in rushing defense, allowing an average of 135.8 yards on the ground.

In the Cleveland Browns' 27-26 loss to New England on Sunday, quarterback Jason Campbell lit up the Patriots for 391 yards and three touchdowns through the air.

Jason Campbell?

As for the Ravens, let's not get into the numbers. We just have to look back at Sunday's win against the Vikings and see that they gave up 41-yard run and a 79-yard pass reception for touchdowns in the last 1:27 of the game.

That is supposed to happen elsewhere, but not in Baltimore. What the heck is going on here?

Let's start with the salary cap. If a team finds a franchise-caliber quarterback like a Manning, Tom Brady or Drew Brees, then it has to pay him a zillion dollars. Once that happens, the team is virtually obligated to invest in a big-name receiver and dominant left tackle. That means more money on offense, less on defense.

Owners and coaches don't mind putting money into offense, because the league prefers high-scoring 31-28 wins over 6-3 slugfests. All the recent rules changes favor offenses.

Breathe on a quarterback? Penalty. Hit a receiver coming across the middle in the chest? Penalty.

Two of the worst calls over the weekend were against Cleveland defensive back Leon McFadden and Minnesota linebacker Chad Greenway; McFadden was called for pass interference late in the game against Patriots receiver Josh Boyce, and Greenway was flagged for interference on tight end Dennis Pitta in the final minute.

Both calls were bogus, but apparently the officials got the league memo about making the game more entertaining and fun for fans.

Besides the salary cap and rules, defensive coordinators have had to deal with the creation of spread and option offenses. We're seeing more athletic players on offense than defense.

For example, Stoney Case wasn't much of a quarterback in Baltimore in 1999, but he could be effective now because of his running ability and playmaking opportunities outside the pocket.

He wouldn't win a Super Bowl, because most of the plays still have to be made from the pocket, but he could win games and possibly take a team to the playoffs.

A lot has changed since 2000. Back then, a team could be one-dimensional and invest most of its money on the defensive side of the ball. Not anymore.

Poor defensive coordinators. They aren't just lacking in talent, but league rules have cut down on live tackling in practices.

It was interesting watching the Ravens play Sunday because their new offense started looking like the old offense. In the previous weeks, quarterback Joe Flacco was throwing the ball deep more. But against Minnesota, he had his security blanket back in Pitta, and Ray Rice became more of a factor out of the backfield.

The Ravens are preparing where they need to go. It used to be that good offenses won games, but great defenses won championships.